For new watches, you could looks at PMWF's "Sales Corner". They are mainly watches made for the Asian market, and they tend to be smaller.
There are loads of sizes of Sandoz HK, including 31mm Explorer styles:
(sapphire + solid bracelet for $250 shipped to US)
This Octo is one of the cheapest ETA movement autos you will find, and it is 36mm, but will wear smaller because of the big bezel:
This one is only 34mm:
And Enicar, with a Swiss ETA (brass colored ETA movements are assembled in Asia), sapphire and solid links:
I'm not clear on what is so expensive about vintage; you can pick up a lot of vintage watches on ebay for under $40, even if it needs to be serviced, you are still talking about less than $160 (maybe less if servicing is cheaper where you are). I picked up a nearly perfect 1960's manual wind Enicar a few weeks back that is running great.